Method and apparatus for facilitating wear leveling of solid state disk
Embodiments of the present disclosure relate to a method and apparatus for facilitating wear leveling of a solid state disk (SSD). The method comprises obtaining a performance parameter of a SSD device of a plurality of SSD devices in the SSD cache, and the SSD device includes one or more SSD disks. The method further comprises determining a weight for the SSD device based on the performance parameter of the SSD device. The method also comprises setting reserved space for the SSD device according to the weight for the SSD device, and the reserved space is inaccessible in the SSD device.
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This application claim priority from Chinese Patent Application Number CN201511021163.9, filed on Dec. 30, 2015 at the State Intellectual Property Office, China, titled “METHOD AND APPARATUS FOR FACILITATING WEAR LEVELING OF SSD” the contents of which is herein incorporated by reference in its entirety.
FIELDEmbodiments of the present disclosure generally relate to storage technology and more specifically relate to a method and apparatus for facilitating wear leveling of a solid state disk (SSD).
BACKGROUNDWith the development of storage technology, the solid state disk (SSD) has been widely used. Compared with the traditional hard disk drive (HDD), SSD has advantages such as fast speed and low power consumption. Generally, a HDD storage system uses a SSD with hundreds of GBs or TBs as its cache space to store frequently accessed hot data in order to accelerate data access of HDD storage system.
The lifecycle of the SSD is greatly impacted by writing operation, which is different from HDD. Too many writing operations would render the SSD unreliable. Thus, the number of writing operations that can be performed by a SSD flash disk is limited and varies according to the type of SSD. For example, the number of writing operations that can be performed by multi-level cell (MLC) is only a tenth of that of a single-level cell (SLC), while the number of writing operations that can be performed by a three-level cell (TLC) is only a tenth of that of the MLC. Furthermore, the lifecycle of the SSD is affected by disk temperature and working current of the SSD. When the temperature or working current is high, the wearing extent of SSD will be great, thereby causing more SSD data blocks to break down.
In some cases, some disks will cause serious wearing due to a large number of writing operations such that the overall performance of SSD cache deteriorates, thereby rendering SSD cache instable or inaccessible. The traditional storage system would generally slow down wearing speed of the SSD disk by limiting the frequency of accessing SSD. However, since the frequency of accessing the storage system is reduced, the overall performance of the storage system would also deteriorate correspondingly.
SUMMARYAccording to an aspect of the present disclosure, a method for facilitating wear leveling of a solid state disk is provided. The method comprises obtaining a performance parameter of a SSD device of a plurality of SSD devices in the SSD cache, and the SSD device comprises one or more SSD disks. The method further comprises determining a weight for the SSD device based on the performance parameter of the SSD device. The method also includes setting reserved space for the SSD device according to the weight for the SSD device, and the reserved space is inaccessible in the SSD device.
According to another aspect of the present disclosure, an apparatus for facilitating wear leveling of a solid state disk is provided. The apparatus comprises an obtaining unit configured to obtain a performance parameter of a SSD device of a plurality of SSD devices in the SSD cache, and the SSD device comprises one or more SSD disks. The apparatus further comprises a determining unit configured to determine a weight for the SSD device based on the performance parameter of the SSD device. The apparatus also comprises a setting unit configured to set reserved space for the SSD device according to the weight for the SSD device, and the reserved space is inaccessible in the SSD device.
According to another aspect of the present disclosure, an apparatus for facilitating wear leveling of a solid state disk is disclosed. The apparatus comprises a memory and a processor. The processor is configured to obtain a performance parameter of a SSD device of a plurality of SSD devices in a SSD cache, wherein the SSD device comprises one or more SSD disks; to determine a weight for the SSD device based on the performance parameter of the SSD device; and to set reserved space for the SSD device according to the weight for the SSD device, wherein the reserved space is inaccessible in the SSD device.
In the illustrative embodiments of the present disclosure, wear of each of the SSD disks can be leveled, thereby lengthening lifecycle of the SSD disk and enhancing stability of SSD cache effectively.
Features, advantages and other aspects of various embodiments of the present disclosure will become more apparent in conjunction with the accompanying drawings with reference to the following detailed depiction, and several embodiments of the present disclosure are illustrated here in an example, but non-limitative, manner, in the accompanying drawings:
Various example embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The flow diagrams and block diagrams in the accompanying drawings illustrate system architecture, functions, and operations which are possibly implemented by the method and system according to various embodiments of the present disclosure. It should be understood that each block in the flow diagrams or block diagrams may represent a unit, a program segment, or a part of code; the unit, program segment, or part of code may include one or more executable instructions for implementing logical functions as prescribed in various embodiments. It should also be noted that in some alternative implementations, the functions indicated in the blocks may also occur in a sequence different from what is indicated in the drawings. For example, two consecutively expressed blocks actually may be executed substantially in parallel, or they sometimes may be executed in a reversed order, dependent on the involved functions. Likewise, it should be noted that each block in the flow diagrams and/or block diagrams, and a combination of blocks in the flow diagrams and/or block diagrams, may be implemented using a specific hardware-based system that performs prescribed functions or operations, or may be implemented using a combination of specific hardware and computer instructions.
The terms “comprise,” “include” and similar terms as used herein should be understood as open terms, that is, “comprise/include, but not limited to”. The term “based on” refers to “based at least partially on.” The term “one embodiment” refers to “at least one embodiment”. The term “another embodiment” or “a further embodiment” indicates “at least one further embodiment”. Relevant definitions of other terms will be provided in the depiction below.
Generally, a certain reserved space is configured for SSD disk to lengthen the lifecycle of a SSD disk. However, in the conventional design of SSD cache, the ratio between the reserved space and the whole space of SSD disk is fixed. For example, a ratio between the reserved space and the whole space is configured for each SSD disk, and the reserved space is the storage space that cannot be accessed in the SSD disk. As shown in
In some cases, the accessing operation transmitted to SSD device 102 may be a random writing operation, which might cause the temperature and working current of SSD device 102 to increase significantly. If the writing operations are too frequent, the wearing speed of SSD device 102 would be faster than the other three SSD devices, i.e., SSD device 101, 103 and 104. Even more serious is that due to rapid increase of the temperature and working current of the SSD device 102, failure block(s) of SSD device 102 increases significantly. However, a fixed ratio of reserved space in each SSD device in the prior art is configured without taking into consideration of impact of the temperature and the working current on the individual SSD lifecycle.
As shown in
In some embodiments, a plurality of SSD devices may form SSD cache in a storage system. The storage system may comprise other disk devices (e.g. HDD) as the main storage medium while the SSD may be used as the cache in the HDD storage system. Optionally, SSD cache uses cache page to store frequently accessed hot data in the HDD, and the hot data are random data and can be smaller than for example 64 KB. Alternatively, the magnitude of each cache page may be adjusted according to actual needs.
In some embodiments. the performance parameter of SSD device represents the current working state of the SSD device. The current wearing extent of SSD device may be determined based on the obtained performance parameter of the SSD device. In some embodiments, the performance parameter may be a temperature, a working current or a wearing ratio of SSD device. For instance, the current temperature of a SSD device is 30° C., its current working current is 1A, and its current wearing ratio is 1%. In another embodiment, the performance parameter may be the number of times of writing operations to the SSD device. For instance, the SSD device has been written for 300 times.
In some embodiments, the performance parameter of each of the plurality of SSD devices can be obtained periodically. For example, the temperature and working current of each SSD device are obtained every day or every three hours. Alternatively, a warning condition may be configured, and the operation of obtaining performance parameter of the SSD device is triggered based on the warning condition. For example, when the temperature of a certain SSD device is higher than 40° C. or the working current is greater than 1.2A, the performance parameter of each of the plurality of SSD devices is obtained.
Next, the method 300 proceeds to step 304, a weight for each SSD device is determined based on the performance parameter of the respectively SSD device. For example, the weight for each SSD device is determined based on the temperature, the working current or the wearing ratio of SSD device. The weight for each SSD device may be in direct proportion or in inverse proportion to the value of its performance parameter. For example, the weight for the SSD device n may be represented as wn=f(t, I, e), wherein t denotes the temperature of the SSD device n, I represents working current of the SSD device n and e denotes the amount of data that has been worn in the SSD device n. When t increases, the value of wn is increased; and when I increases, the value of wn is also increased. Generally, the higher SSD disk temperature is, or the bigger the working current is, the more likely that the disk is damaged.
In some embodiments, the weight can be configured so that it increases as the performance parameter increases. Alternatively, the weight can be configured so that it decreases as the performance parameter decreases. That is, the bigger the value of the performance parameter is, the greater the weight for the SSD device is. Optionally, in the preliminary condition, each SSD device has the same temperature, working current and wearing ratio so that the weight value of each SSD device can be equal, for example, set to 1.
Next, at step 306, the reserved space for each SSD device is configured based on the weight for each SSD device. The storage space for each SSD device can be divided into available space and reserved space, and the available space is the storage space that can be accessed in the SSD device, while the reserved space is the inaccessible storage space in the SSD device. The reserved space may be set based on the weight, which can slow the wearing extent of the SSD device with higher wearing extent. For example, the weight for SSD device is son=s*r*f(w0, w1, w2, . . . , wn), wherein s denotes the whole storage space for SSD device n, r is the ratio of the default reserved space of SSD device n, and wn is the weight for SSD device n. For example, there are 4 devices, the storage space of each device is 100 GB, and default reserved percentage is 50%, and the initial weight is 1, and thus the initial reserved space for each SSD device is 50 GB. After the SSD device runs for a period of time, since the accessing times of each SSD device is different, each SSD device has different temperatures, working currents and wearing ratios, and thus each SSD device has different weight and reserved space. Table 1 shows the reserved space of the SSD devices at a point of time.
As shown in table 1, the greater the weight for a SSD device is, the larger the reserved space of the SSD device will be. Optionally, for a SSD device with the biggest weight, the reserved space can be configured with the biggest ratio. Alternatively, for SSD device with the smallest weight, the reserved space can be configured with the smallest ratio.
Generally speaking, the accessing frequency of the SSD device is in direct proportion to the available space of the SSD device. Therefore, the accessing times of the SSD device and the reserved space of the SSD device are in inverse proportion. That is, when a specific SSD device is configured with the largest ratio of reserved space, the number of times that the specific SSD device is written is the smallest, and when the specific SSD device is configured with the smallest ratio of reserved space, the number of times that the specific SSD device is written is the largest. Therefore, the reserved space of the SSD device with greater wearing ratio will increase, and its wearing speed will decrease; the reserved space of the SSD device with lower wearing, ratio will decrease, and its wearing speed will increase, so that all the SSD devices in the whole SSD cache will achieve wear leveling.
In some embodiments, the storage space of each SSD device may be 100 GB and comprise a plurality of cache pages. In some embodiments, each cache page may be 64 KB, and 1,620,000 pages exist for each SSD device. Under the default condition, if the default reserved space is 50 GB, then 810,000 available pages and 810,000 reserved pages may exist for each SSD device.
In an embodiment, the weight may be configured for each SSD device. For instance, the weight may be configured so that it increases as the performance parameter increases. Alternatively, the weight can be configured so that it decreases as the performance parameter decreases. That is, the, bigger the value of the performance parameter is, the greater the SSD device weight is. Alternatively, in the default condition, each SSD device has the same temperature, the same working current and the same wearing ratio so that the weight value of each SSD device can be equal, for example, set to 1.
After the new reserved space for each SSD device is configured, since SSD device 401, 403 and 404 have more available space, writing operations for the three SSD devices will be increased, and their temperature and working current will also increase correspondingly. As to SSD device 402, because it has the smallest available space, its writing operations will decrease significantly. Therefore, after a period of time, the weight for SSD device 402 will decrease while the weights for SSD device 401, 403 and 404 will increase. Correspondingly, the reserved space of SSD device 402 is decreased, the reserved spaces of SSD device 401, 403 and 404 are increased, and the state of each SSD device in the SSD cache returns to the default condition shown in
In some embodiments, the SSD cache uses cache page(s) to store hot data frequently accessed in a hard disk drive (HDD). Alternatively, the hot data is random data and its size may be smaller than 64 KB.
In some embodiments, the performance parameter may comprise at least one of the following: a temperature, a working current and a wearing ratio. Optionally, the obtaining unit 602 may be further configured to r obtain the performance parameter of the SSD device periodically. In another embodiment, the determining unit 604 is configured to set the weight for the SSD device so that the weight increases as the performance parameter increases; and/or configuring the weight for the SSD device so that the weight decreases as the performance parameter decreases. Alternatively, the default weight for each SSD device is the same.
In some embodiments, the setting unit 606 may be further configured to set the reserved space greater than threshold space in response to the weight being above a predetermined threshold; and/or setting the reserved space less than threshold space in response to the weight being below the predetermined threshold. For example, the setting unit 606 may be configured to set the biggest ratio of reserved space for SSD device having the biggest weight; and/or set the smallest ratio of reserved space for SSD device having the smallest weight. In some embodiments, when a specific SSD device is configured with the reserved space with the biggest ratio, the number of times that the specific SSD device is written is the smallest; and/or when the specific SSD device is configured with a reserved space with the smallest ratio, the number of times that the specific SSD device is written is the largest.
Hereinafter, a computer device in which embodiments of the present disclosure may be implemented will be described with reference to
The computer device as shown in
The present descriptions above are only optional embodiments, not intended to limit the present disclosure. To those skilled in the art, embodiments of the present disclosure may have various modifications and variations. Any modifications, equivalent replacements, and improvements within the spirit and principle of embodiments of the present disclosure should be included within the protection scope of embodiments of the present disclosure.
Claims
1. A method for facilitating wear leveling for a solid state disk (SSD), comprising: wherein setting the reserved space for the SSD device according to the weight for the SSD device comprises at least one of the following: wherein
- obtaining a performance parameter of a SSD device of a plurality of SSD devices in a SSD cache, the SSD device including one or more SSD disks, wherein the performance parameter is enabled to comprise temperature of the SSD device;
- determining a weight for the SSD device based on the performance parameter of the SSD device; and
- setting reserved space for the SSD device according to the weight for the SSD device, the reserved space being inaccessible in the SSD device;
- setting the reserved space greater than a threshold space in response to the weight being above a predetermined threshold, and
- setting the reserved space less than the threshold space in response to the weight being below the predetermined threshold; and
- if the reserved space is set to be greater than the threshold space, a writing frequency of the SSD device is set to be less than a threshold frequency, and
- if the reserved space is set to be less than the threshold space, the writing frequency of the SSD device is set to be greater than the threshold frequency.
2. The method according to claim 1, wherein the SSD cache uses a cache page to store hot data frequently accessed in a hard disk drive (HDD).
3. The method according to claim 2, wherein the hot data is random data with a size below 64 KB.
4. The method according to claim 1, wherein the obtaining a performance parameter of a SSD device of a plurality of SSD devices in a SSD cache comprises:
- periodically obtaining the performance parameter of the SSD device.
5. The method according to claim 4, wherein the determining a weight for the SSD device based on the performance parameter of the SSD device comprises at least one of the following:
- configuring analysis of the weight for the SSD device so that the weight increases as the performance parameter increases; and
- configuring analysis of the weight for the SSD device so that the weight decreases as the performance parameter decreases.
6. The method according to claim 5, wherein the plurality of SSD devices has a same default weight.
7. The method according to claim 1, wherein the performance parameter further includes at least one of a working current and a wearing ratio.
8. The method according to claim 1, wherein the performance parameter of the SSD device is obtained periodically in response to expiration of a predefined time period; and
- wherein the method further comprises: detecting that the temperature of another SSD device of the plurality of SSD devices is higher than a predefined temperature threshold, and in response to detecting that the temperature of the other SSD device is higher than the predefined temperature threshold, obtaining the performance parameter of each SSD of the plurality of SSD devices.
9. An apparatus for facilitating wear leveling for a solid state disk (SSD), comprising: wherein the setting unit is configured to perform at least one of the following: wherein
- an obtaining unit configured to obtain a performance parameter of a SSD device of a plurality of SSD devices in a SSD cache, the SSD device including one or more SSD disks, wherein the performance parameter is enabled to comprise temperature of the SSD device;
- a determining unit configured to determine a weight for the SSD device based on the performance parameter of the SSD device; and
- a setting unit configured to set reserved space for the SSD device according to the weight for the SSD device, the reserved space being inaccessible in the SSD device;
- setting the reserved space greater than a threshold space in response to the weight being above a predetermined threshold, and
- setting the reserved space less than the threshold space in response to the weight being below the predetermined threshold, and
- if the reserved space is set to be greater than the threshold space, a writing frequency of the SSD device is set to be less than a threshold frequency, and
- if the reserved space is set to be less than the threshold space, the writing frequency of the SSD device is set to be greater than the threshold frequency.
10. The apparatus according to claim 9, wherein the SSD cache uses a cache page to store hot data frequently accessed in a hard disk drive (HDD).
11. The apparatus according to claim 10, wherein the hot data is random data with a size below 64 KB.
12. The apparatus according to claim 9, wherein the obtaining apparatus is further configured to:
- periodically obtain the performance parameter of the SSD device.
13. The apparatus according to claim 12, wherein the determining apparatus is configured to perform at least one of the following:
- configuring the weight for the SSD device so that the weight increases as the performance parameter increases; and
- configuring the weight for the SSD device so that the weight decreases as the performance parameter decreases.
14. The apparatus according to claim 13, wherein the plurality of SSD devices has a same default weight.
15. The apparatus according to claim 9, wherein the performance parameter further includes at least one of a working current and a wearing ratio.
16. The apparatus according to claim 9, wherein the obtaining unit obtains the performance parameter of the SSD device periodically in response to expiration of a predefined time period; and
- wherein the obtaining unit is further configured to: detect that the temperature of another SSD device of the plurality of SSD devices is higher than a predefined temperature threshold, and in response to detecting that the temperature of the other SSD device is higher than the predefined temperature threshold, obtain the performance parameter of each SSD of the plurality of SSD devices.
17. The apparatus according to claim 9, wherein the processor obtains the performance parameter of the SSD device periodically in response to expiration of a predefined time period; and
- wherein the processor is further configured to: detect that the temperature of another SSD device of the plurality of SSD devices is higher than a predefined temperature threshold, and in response to detecting that the temperature of the other SSD device is higher than the predefined temperature threshold, obtain the performance parameter of each SSD of the plurality of SSD devices.
18. An apparatus for facilitating wear leveling of a solid state disk SSD, comprising: wherein the processor, when setting the reserved space for the SSD device according to the weight for the SSD device, is constructed and arranged to perform at least one of the following: wherein
- a memory; and
- a processor configured to: obtain a performance parameter of a SSD device of a plurality of SSD devices in a SSD cache, the SSD device including one or more SSD disks, wherein the performance parameter is enabled to comprise temperature of the SSD device; determine a weight for the SSD device based on the performance parameter of the SSD device; and set reserved space for the SSD device according to the weight for the SSD device, the reserved space being inaccessible in the SSD device;
- set the reserved space greater than a threshold space in response to the weight being above a predetermined threshold, and
- set the reserved space less than the threshold space in response to the weight being below the predetermined threshold; and
- if the reserved space is set to be greater than the threshold space, a writing frequency of the SSD device is set to be less than a threshold frequency, and
- if the reserved space is set to be less than the threshold space, the writing frequency of the SSD device is set to be greater than the threshold frequency.
8010738 | August 30, 2011 | Chilton et al. |
8046551 | October 25, 2011 | Sahin |
8130554 | March 6, 2012 | Linnell |
8775723 | July 8, 2014 | Suzuki |
8880801 | November 4, 2014 | Robins et al. |
8996951 | March 31, 2015 | Hyde |
9104326 | August 11, 2015 | Frank et al. |
9208162 | December 8, 2015 | Hallak et al. |
9286003 | March 15, 2016 | Hallak et al. |
9304889 | April 5, 2016 | Chen et al. |
9342465 | May 17, 2016 | Meiri |
9367398 | June 14, 2016 | Ben-Moshe et al. |
9378106 | June 28, 2016 | Ben-Moshe et al. |
9396243 | July 19, 2016 | Halevi et al. |
9418131 | August 16, 2016 | Halevi et al. |
9442941 | September 13, 2016 | Luz et al. |
9606870 | March 28, 2017 | Meiri et al. |
9652352 | May 16, 2017 | Chilton et al. |
9665305 | May 30, 2017 | Natanzon et al. |
9811288 | November 7, 2017 | Chen et al. |
9910791 | March 6, 2018 | Dibb et al. |
9946471 | April 17, 2018 | More et al. |
9996539 | June 12, 2018 | Natanzon |
10025843 | July 17, 2018 | Meiri et al. |
10042751 | August 7, 2018 | Veprinsky et al. |
10055161 | August 21, 2018 | Meiri et al. |
10082965 | September 25, 2018 | Tamilarasan et al. |
20090119448 | May 7, 2009 | Hsu |
20130013850 | January 10, 2013 | Baderdinni |
20130166614 | June 27, 2013 | Watanabe |
20140136915 | May 15, 2014 | Hyde |
20140156911 | June 5, 2014 | Alcantara |
20150199152 | July 16, 2015 | Asnaashari |
20150212755 | July 30, 2015 | Asnaashari |
20160062693 | March 3, 2016 | Samuels |
20160117105 | April 28, 2016 | Thangaraj |
20170329684 | November 16, 2017 | Lien |
20180089095 | March 29, 2018 | Li |
103731505 | April 2014 | CN |
Type: Grant
Filed: Dec 22, 2016
Date of Patent: Aug 6, 2019
Patent Publication Number: 20170192695
Assignee: EMC IP Holding Company LLC (Hopkinton, MA)
Inventors: Xinlei Xu (Beijing), Liam Xiongcheng Li (Beijing), Jian Gao (Beijing), Lifeng Yang (Beijing), Ruiyong Jia (Beijing)
Primary Examiner: Sean D Rossiter
Application Number: 15/387,744
International Classification: G06F 13/00 (20060101); G06F 3/06 (20060101); G06F 12/0802 (20160101);